Banana peel biochar as alternative source of potassium for plant productivity and sustainable agriculture

Abstract

Purpose Biochar addition to soil is immensely beneficial for increasing plant productivity and C sequestration, attenuating nutrient leaching loss, counteracting heavy metal contamination and organic waste triggered environmental pollution. To understand the sustainable benefits of biochar, two pot experiments were conducted under net house condition in Khulna University, Bangladesh. Methods Biochar was prepared from banana peel waste through slow pyrolysis process under limited oxygen condition. Three lower rates (1, 2 and 3%) of banana peel biochar (BPB) were added with agricultural soil along with control with three replications for each. After incorporation of BPB into soil, pots were kept under field condition for 7 days and then the seeds of Ipomoea aquatica were sown. Plants were harvested after 42 days from seeds sowing and plant height, leaf number, fresh weight, and dry weight were measured. Another pot experiment was also conducted under sand medium to test the BPB as K-rich soil amendment where K was applied from two different sources (KCl and BPB) along with control. Seeds of Cucurbita moschata were sown and 40 days after seed sowing, K deficiency was observed in control treatments. Results Banana peel biochar was found to be rich in K content. Plant productivity and above-ground biomass were reduced in 1% BPB treatments, but increased in 2 and 3% BPB treatments as compared to control but statistically insignificant (p < 0.05). In case of second experiment, K deficiency symptoms were observed in 40 days aged Cucurbita moschata seedlings under control treatments, whereas no K deficiency symptom was noticed in plants grown under K supplied from both KCl and BPB. Moreover, the plant grown with BPB was found healthy, stronger and greener in appearance. Conclusion This positive influence of BPB on plant growth suggests the alternative way to overcome the use of chemical fertilizer and effective way of utilization of agricultural wastes through recycling.

Tangerine, banana and pomegranate peels valorisation for sustainable environment: A review

“…Documentary review of scientific articles over the last decade has revealed that TPW, PPW and BPW have successfully used as fertilisers for improving soil fertility and enriching soil microbiota thanks to their content of minerals required for the plant's growth. TPW, PPW and BPW have a high content of the most nutritious minerals, mainly phosphorus (P), potassium (K), sodium (Na), iron (Fe), zinc (Zn), manganese (Mn) and copper (Cu) [ 19 , 148 ]. BPW is an organic waste rich in high potassium (K) content compared to TPW and BPW [ 149 ], also other authors have shown that BPW biochar was found to be high in potassium (K) which could be used as potassium (K) fertilizer, therefore, an alternative source of potassium (K) for plants productivity [ 19 ].…”

“…TPW, PPW and BPW have a high content of the most nutritious minerals, mainly phosphorus (P), potassium (K), sodium (Na), iron (Fe), zinc (Zn), manganese (Mn) and copper (Cu) [ 19 , 148 ]. BPW is an organic waste rich in high potassium (K) content compared to TPW and BPW [ 149 ], also other authors have shown that BPW biochar was found to be high in potassium (K) which could be used as potassium (K) fertilizer, therefore, an alternative source of potassium (K) for plants productivity [ 19 ]. Consequently, BPW biochar is not recommended for soil acidity remediation, but it would certainly reduce calcareous requirements when applied as a potassium (K) fertilizer [ 150 ].…”

“…Anastopoulos et al [ 18 ] have also demonstrated that the incorporation of TPW and BPW in soil has a significant effect on the bacterial community structure and the bacterial guild abundance associated with nitrous oxide emissions. The usage of TPW, PPW and BPW or their biochar have also helped plants to resist diseases [ 19 , 151 , 153 ]. Furthermore, the spread of unstable TPW, PPW and BPW to soil could result the depletion of soil oxygen and the emission of harmful odours in treated crop fields.…”

“…Every TPW, PPW and BPW valorisation pathway depends on a high number of factors affecting economic viability [ [12] , [13] , [14] ]. TPW, PPW and BPW may be used directly or after treatments as animal feed [ 15 , 16 ], soil amendment [ [17] , [18] , [19] ], bio-adsorbents [ 20 , 21 ], and the production of the outputs was obtained by the biorefinery process (biogas, bioethanol and biohydrogen) [ [22] , [23] , [24] , [25] , [26] ]. Numerous other studies have focused on the valorisation of TPW, PPW and BPW for the production of value-added products (essential oil, enzymes, food, medical and cosmetic products) [ [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] ].…”

Biochar from vegetable wastes: agro-environmental characterization

“…Mazac (2016) prepared five different batches of mixed food wastes including vegetables, fruits, leaves and egg shells to produce biochar at a slow pyrolysis temperature condition of 260 °C for 3 and 6 h and tested them with tomato plants (Solanum lycopersicum) over 30 days. Similarly, Islam et al (2019) tested banana peel biochar produced at 400 °C for 2 h duration and tested it at 1, 2 and 4% loading with Ipomoea aquatica. Although both experiments observed improved yield with biochar, neither test showed statistically significant differences.…”